Power conversion apparatus and junction box

ABSTRACT

A power conversion apparatus capable of cheaply securing safety and achieving watertightness. The power conversion apparatus ( 100 ) has: a charging device ( 14 ) for charging from an external power source ( 20 ) to a cell ( 30 ); an inverter ( 13 ) for converting the current of the cell ( 30 ) from direct current to alternating current and supplying the current to a motor ( 40 ); and a junction box ( 15 ) for relaying an electrical connection. The inverter ( 13 ), the charging device ( 14 ), and the junction box ( 15 ) are contained in a single housing. Also, the charging device ( 14 ) and the junction box ( 15 ) are electrically connected, and the junction box ( 15 ) and the inverter ( 13 ) are electrically connected. Also, the junction box ( 15 ) and the inverter ( 13 ) are connected by a bus bar ( 16 ).

TECHNICAL FIELD

The present invention relates to a power conversion apparatus and ajunction box to be installed in a vehicle.

BACKGROUND ART

In recent years, electric vehicles (EVs) or plug-in hybrid electricvehicles (PHEVs) have become popular. These vehicles each include: abattery; a charging apparatus configured to charge the battery using anexternal power supply (commercial power supply); an inverter configuredto convert a direct current from the battery to an alternating-current;and a motor configured to drive a wheel of the vehicle using thealternating-current from the inverter (e.g., see Patent Literature(hereinafter, referred to as “PTL”) 1. These devices are electricallyconnected to each other.

CITATION LIST Patent Literature PTL 1 Japanese Patent ApplicationLaid-Open No. 2012-240477 SUMMARY OF INVENTION Technical Problem

The technique disclosed in PTL 1 adopts a harness as a means forelectrical connection, thus connecting devices respectively housed indifferent casings to each other via a harness. Accordingly, thetechnique disclosed in PTL 1 has the following problems.

More specifically, the harness is exposed to the outside of each casing,so that processing to coat the harness with an insulator and/orwaterproofing needs to be applied to the harness in order to ensuresafety. Such processing requires costs.

Moreover, use of a harness requires custom processing for a connectionportion of the harness in each connection-target device. Such processingrequires costs as well.

An object of the present invention is to ensure safety as well as toachieve complete waterproofing without additional costs.

Solution to Problem

A power conversion apparatus according to an aspect of the presentinvention includes: a charging apparatus that charges a battery using anexternal power supply; an inverter that converts a current of thebattery from a direct current to an alternating-current and thatsupplies the alternating-current to a motor; and a junction box thatrelays electrical connection, in which the inverter, the chargingapparatus, and the junction box are housed in a single casing, and thecharging apparatus and the junction box are electrically connected toeach other while the junction box and the inverter are electricallyconnected to each other, in which the junction box and the inverter areconnected to each other via a bus bar.

A junction box according to an aspect of the present invention includesa protruding portion to be inserted into an opening formed in apartition member of a casing that is internally divided into a pluralityof spaces by the partition member, in which the protruding portionincludes an insulation portion and serves as a connection portion for abus bar.

Advantageous Effects of Invention

According to the present invention, it is made possible to ensure safetyas well as to achieve complete waterproofing without additional costs.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram illustrating an example of a power conversionapparatus according to Embodiment 1 of the present invention;

FIG. 2 is an exploded perspective view illustrating an example of thepower conversion apparatus according to Embodiment 1 of the presentinvention;

FIG. 3 is a lateral cross-sectional view illustrating an example of thevicinity of a fastening portion of the power conversion apparatusaccording to Embodiment 1 of the present invention;

FIG. 4 is a lateral cross-sectional view illustrating an example of thevicinity of a bus bar according to Embodiment 1 of the presentinvention;

FIGS. 5A and 5B are each a lateral cross-sectional view illustrating anexample of a vehicle installation position for the power conversionapparatus according to Embodiment 1 of the present invention;

FIG. 6 is an exploded perspective view illustrating an example of apower conversion apparatus according to Embodiment 2 of the presentinvention;

FIG. 7 is an exploded perspective view illustrating an example of thestructures of work windows and lids of the power conversion apparatusaccording to Embodiment 2 of the present invention;

FIG. 8 is a perspective view illustrating an example of how the lids arefixed to the work windows of the power conversion apparatus according toEmbodiment 2 of the present invention;

FIG. 9 is a front view illustrating an example of the work windows ofthe power conversion apparatus according to Embodiment 2 of the presentinvention;

FIG. 10 is a front view illustrating an example of how a first lid isfixed to the work window of the power conversion apparatus according toEmbodiment 2 of the present invention;

FIG. 11 is a front view illustrating an example of how the first lid anda second lid are fixed to the work windows of the power conversionapparatus according to Embodiment 2 of the present invention; and

FIG. 12 is a plan view illustrating an example of an interlock mechanismof the power conversion apparatus according to Embodiment 2 of thepresent invention.

DESCRIPTION OF EMBODIMENTS Embodiment 1

Hereinafter, a description will be given of a power conversion apparatusaccording to Embodiment 1 of the present invention with reference to theaccompanying drawings.

FIG. 1 is a block diagram illustrating a configuration example of thepower conversion apparatus according to Embodiment 1.

In FIG. 1, power conversion apparatus 100 is an apparatus to beinstalled in a vehicle such as an EV and includes: casings 11 and 12;inverter 13, which serves as a power conversion circuit; chargingapparatus 14; and junction box 15. In power conversion apparatus 100, asingle casing is formed by combination of casing 11 (an example of afirst casing) and casing 12 (an example of a second casing) and isdivided into casings 11 and 12 by partition member 10. Partition member10 is a member serving as the bottom of casing 12 (hereinafter, may bereferred to as “bottom member”).

Casings 11 and 12 are molded using an aluminum cast, for example, andare heat-resistant and rigid. Casings 11 and 12 are ensured forairtightness in order to prevent entry of a water droplet or dust or thelike into casing 11 and 12, respectively.

Casing 11 includes inverter 13 in an inner portion (an example of afirst space) of casing 11. Inverter 13 converts a direct current (orDC-power) supplied from battery 30 to a three-phase alternating-current(or AC power) and outputs the current to motor 40.

Meanwhile, casing 12 includes charging apparatus 14 and junction box 15in an inner portion (an example of a second space) of casing 12.Charging apparatus 14 includes an AC-DC conversion circuit and/or aDC-DC conversion circuit and receives power from external power supply20 and generates a charging voltage for battery 30. Junction box 15 isan apparatus configured to relay electrical connection between battery30, charging apparatus 14, and inverter 13 and also to distribute theflow of power, and is called an electricity distribution box.

Charging apparatus 14 is electrically connected to external power supply(commercial power supply) 20 via an external connector (not illustrated)and electrically connected to junction box 15. For example, chargingapparatus 14 and junction box 15 are connected via a bus bar.

Junction box 15 is connected to battery 30 via a harness, for example.Thus, charging apparatus 14 converts power from external power supply 20into a direct current from an alternating-current, and charges, viajunction box 15, battery 30, which is installed in the vehicle. Battery30 is a secondary battery configured to store power for driving motor40.

Inverter 13 is electrically connected to motor 40 and is alsoelectrically connected to junction box 15. Inverter 13 and junction box15 are connected to each other via bus bar 16. Bus bar 16 is made ofmetal (e.g., made of copper) and has the positive pole and negativepole. Bus bar 16 passes through opening 17, which is formed in partitionmember 10, and connects inverter 13 and junction box 15 together. Thus,inverter 13 converts a current supplied from battery 30 via junction box15 to an alternating-current (e.g., three-phase alternating-current) andsupplies the current to motor 40, which is mounted in a vehicle. Motor40 drives a wheel of the vehicle using the alternating-current.

FIG. 2 is an exploded perspective view illustrating a configurationexample of the power conversion apparatus according to Embodiment 1.

In FIG. 2, power conversion apparatus 100 is separated into casings 11and 12, and lid 18. Casings 11 and 12, and lid 18 are each made ofmetal.

Casings 11 and 12 each substantially has an open-top cuboid shape.Casing 12 is superimposed on and fastened with casing 11. Bottom member10 of casing 12 serves as a lid portion of casing 11 when superimposedon chasing 11. Meanwhile, the opening of casing 12 is covered by lid 18.Note that, how casings 11 and 12 are fastened together will be describedusing FIG. 3, hereinafter.

In FIG. 2, external power supply connection portion 19, which isdisposed on a side surface of casing 12, serves as an interface forconnection with external power supply 20. In addition, casing 12includes a battery connection portion (not illustrated), which serves asan interface for connection with battery 30, and which is disposed on aside surface opposite to the side surface where external power supplyconnection portion 19 is disposed. Moreover, a motor connection portion(not illustrated), which serves as an interface for connection withmotor 40 is disposed on the bottom of casing 11.

In FIG. 2, casing 12 includes one interlock (not illustrated). Thisinterlock detects that lid 18 has been opened (open state of lid 18).With this detection, the current in power conversion apparatus 100 iscontrolled to stop. Although it will be described hereinafter, afastening portion for fastening casings 11 and 12 is disposed withineach casing. Accordingly, the user always needs to remove lid 18 ofcasing 12 in order for the user to touch the inside of casing 11. Thisconfiguration eliminates the need for an interlock to detect an openingstate of the lid in casing 11. Stated differently, the interlock ofcasing 12 also serves as the interlock for casing 11.

FIG. 3 is a lateral cross-sectional view illustrating a configurationexample of the fastening portion of power conversion apparatus 100according to Embodiment 1.

The fastening portion for fastening casings 11 and 12 is disposed insidecasings 11 and 12. In FIG. 3, the fastening portion is formed of screw21 and screw hole 22, for example. Screw hole 22 is formed in each ofcasings 11 and 12. When casing 11 is appropriately superimposed oncasing 12, single screw hole 22, which is a through hole, is formed.Casings 11 and 12 are fastened together by inserting screw 21 into screwhole 22. Note that, although only one position of the fastening portionis illustrated in FIG. 3, it is preferred that a plurality of fasteningportions identical to the fastening portion mentioned above be disposedinside of each casing.

FIG. 4 is a lateral cross-sectional view illustrating a configurationexample for a position around the bus bar of power conversion apparatus100 according to Embodiment 1. Note that, illustration of the fasteningportion (screw 21 and screw hole 22) illustrated in FIG. 3 is omitted inFIG. 4.

In FIG. 4, junction box 15 is formed in a partially protruding shape.The partially protruding portion of junction box 15 is referred to asprotruding portion 24 and is inserted into opening 17 and serves as aconnection portion (insertion port) for bus bar 16. Protruding portion24 includes a portion near the opening which is formed as insulationportion 23. Furthermore, as described above, bus bar 16 passes throughopening 17 and connects inverter 13 and junction box 15 together.

FIGS. 5A and 5B are each a lateral cross-sectional view illustrating anexample of an in-vehicle installation position of power conversionapparatus 100 according to Embodiment 1. Hereinafter, two examplesillustrated in FIGS. 5A and 5B will be described, respectively. Notethat, the charging apparatus, junction box, inverter, motor, and batteryare denoted by “CHG,” “JB,” “INV,” “M,” and “BAT,” respectively, inFIGS. 5A and 5B.

FIG. 5A illustrates an example in which power conversion apparatus 100is installed in a front portion of vehicle 1. In FIG. 5A, battery 30 isinstalled in a bottom portion (e.g., under the passenger seat) ofvehicle 1. Junction box 15 is installed at a position that allowsjunction box 15 to be connected to battery 30 with the shortest distancein casing 12. As described above, junction box 15 and battery 30 areconnected together via a harness.

FIG. 5B illustrates an example in which power conversion apparatus 100is installed in a rear portion of vehicle 1. In FIG. 5B, battery 30 isinstalled in a bottom portion (e.g., under the passenger seat) ofvehicle 1. Junction box 15 is installed at a position that allowsjunction box 15 to be connected to battery 30 with the shortest distancein casing 12. As described above, junction box 15 and battery 30 areconnected together via a harness.

Power conversion apparatus 100 according to Embodiment 1 described abovecan bring about the following effects.

Power conversion apparatus 100 according to Embodiment 1 ischaracterized in that inverter 13, charging apparatus 14, and junctionbox 15 are housed in a single casing, and charging apparatus 14 andjunction box 15 are electrically connected to each other while junctionbox 15 and inverter 13 are electrically connected to each other, andjunction box 15 and inverter 13 are connected to each other via bus bar16. More specifically, in power conversion apparatus 100 according toEmbodiment 1, a charging apparatus, a junction box, and an inverter areelectrically connected to each other in a single casing, so that thecasing itself can serve as a cover for the electrically connectedportions between these devices. In addition, the electrical connectionaccording to Embodiment 1 allows the charging apparatus, the junctionbox and the inverter to be disposed while being fixed at certainpositions within a limited space inside the casing. For this reason,there is no need to use a harness. Accordingly, power conversionapparatus 100 according to Embodiment 1 can ensure safety and achievecomplete waterproofing without additional costs.

In addition, power conversion apparatus 100 according to Embodiment 1 ischaracterized in that power conversion apparatus 100 includes a singlecasing in which two spaces obtained by dividing the space inside thecasing using partition member 10, while inverter 13 and junction box 15are placed in the two different spaces, respectively, but connected toeach other via bus bar 16 passing through opening 17, which is formed inportion member 10. More specifically, in power conversion apparatus 100according to Embodiment 1, an inverter and a junction box areelectrically connected to each other within a single casing, so that thecasing itself can serve as a cover for the electrical connection portionof the two devices. In addition, the electrical connection according toEmbodiment 1 requires no use of a harness because the chargingapparatus, the junction box and the inverter are fixed at certainpositions within the limited space, which is the space inside thecasing. Accordingly, power conversion apparatus 100 according toEmbodiment 1 can ensure safety and achieve complete waterproofingwithout additional costs.

Power conversion apparatus 100 according to Embodiment 1 ischaracterized in that battery 30 is installed in a rear portion or abottom portion of vehicle 1 while junction box 15 is installed at aposition that makes the distance between junction box 15 and the batteryshortest within power conversion apparatus 100. Thus, power conversionapparatus 100 according to Embodiment 1 can reduce the length of theharness connecting the junction box and the battery together, thusreducing the costs. Note that, higher safety can be achieved in thearrangement illustrated in FIG. 5B than in the arrangement in FIG. 5A.More specifically, in FIG. 5A, it is possible for the user to touchpower conversion apparatus 100 when the hood is open, so that thisarrangement is not very safe. Meanwhile, in FIG. 5B, the user cannottouch power conversion apparatus 10 disposed inside the trunk, even whena rear door is open, so that this arrangement is safe.

Moreover, in power conversion apparatus 100 according to Embodiment 1,protruding portion 24, which is a part of junction box 15, includesinsulation portion 23 and is inserted through opening 17 and serves as aconnection portion for bus bar 16. Thus, power conversion apparatus 100according to Embodiment 1 can avoid an unsafe situation that may occurwhen the bus bar comes into contact with a metal-made opening becausethe screw of the fastening portion comes loose, for example.

Moreover, power conversion apparatus 100 according to Embodiment 1 ischaracterized in that a single casing is divided into the first and thesecond spaces using partition member 10, while casing 11, which formsthe first space, and casing 12, which forms the second space, areseparable, and that casings 11 and 12 include fastening portions forfastening casings 11 and 12 together in the first and the second spaces,respectively. Stated differently, the fastening portions are includedinside the respective casings. Thus, power conversion apparatus 100according to Embodiment 1 can be reduced in length of the lateral widthof the entire casing by the length (width) of the fastening portions,which would otherwise be added to the lateral width of the entire casingwhen the fastening portions are formed outside the respective casings.

Moreover, power conversion apparatus 100 according to Embodiment 1 ischaracterized in that casing 12 is superimposed on and fastened to thecasing 11 inside casings 11 and 12, while power conversion apparatus 100according to Embodiment 1 includes, in casing 12, only one interlock todetect an open state of lid 18 of casing 12. Thus, power conversionapparatus 100 according to Embodiment 1 does not need to include aninterlock in casing 11, thereby making it possible to obtain effectsincluding simplification in shape, a cost reduction for the interlockitself, and a reduction in the number of components required forinstallation of the interlock, for example.

Junction box 15 according Embodiment 1 is characterized by includingprotruding portion 24 to be inserted into opening 17, while protrudingportion 24 includes insulation portion 23 and serves as a connectionportion for bus bar 16. Thus, the junction box according to Embodiment 1makes it possible to avoid an unsafe situation that may occur when thebus bar comes into contact with the metal-made opening portion becausethe screw of the fastening portion comes loose, for example.

The description has been given of Embodiment 1 of the present invention,but the description is an example only, and the following modificationsare possible, for example.

For example, an example is used to describe Embodiment 1, in whichjunction box 15 is included in casing 12 together with chargingapparatus 14, but the present invention is not limited to this example.For example, junction box 15 may be included in casing 11 together withinverter 13.

For example, an example is used to describe Embodiment 1, in which anunsafe situation that may occur when bus bar 16 comes into contact withopening 17 is avoided by including insulation portion 23 in protrudingportion 24 of junction box 15, but the present invention is not limitedto this example. For example, junction box 15 itself may be formed usingan insulator (e.g., resin), or the portion of partition member 10 whereopening 17 is formed may be coated using an insulating member. Thus, asin the case of the presence of insulation portion 23 of protrudingportion 24, it is made possible to avoid an unsafe situation that mayoccur when bus bar 16 comes into contact with opening portion 17 becausescrew 21 comes loose, for example.

Furthermore, a configuration is used to describe Embodiment 1, in whichbattery 30 is installed in a bottom portion of vehicle 1, but thepresent invention is not limited to this configuration. For example,battery 30 may be installed in a front portion or rear portion of thevehicle. In this configuration, junction box 15 is installed at aposition that makes the distance between junction box 15 and battery 30shortest in casing 12.

Furthermore, although a configuration in which inverter 13, chargingapparatus 14, and junction box 15 are housed in power conversionapparatus 100 in Embodiment 1, for example, the present invention is notlimited to this configuration, and another device may be installed inpower conversion apparatus 100. For example, a DC/DC converter may behoused in power conversion apparatus 100. Such a DC/DC converter is usedto supply power to an auxiliary battery (12V), for example, and reducesa high voltage of battery 30 to 12V and outputs the power. Housing theDC/DC converter within power conversion apparatus 100 (e.g., withincasing 12) increases the number of high voltage cables covered by powerconversion apparatus 100, thereby making it possible to further enhancethe safety.

In Embodiment 1, a description has been given of a configuration inwhich power conversion apparatus 100 includes a single casing formed bycombination of casings 11 and 12 while partition member 10 serves as abottom member for casing 12, but the present invention is not limited tothis configuration. For example, a single casing without combination ofa plurality of casings (single casing that cannot be separated into aplurality of casings) may be employed. Moreover, partition member 10 maybe a member that simply divides a space. Note that, the number ofpartition members 10 is not limited to one, and may be two or more.

Embodiment 2

Hereinafter, a description will be given of a power conversion apparatusaccording to Embodiment 2 of the present invention with reference to theaccompanying drawings.

Background and Problems According to Embodiment 2

In recent years, vehicles provided with a running motor, such as hybridelectric vehicles (HEVs), plug-in HEVs (PHEVs), or electric vehicles(EVs) have become popular. These vehicles may be provided with ahigh-output motor such as a motor for driving a lifting machine, acrane, or a power compressor.

These vehicles are provided with a power conversion apparatus configuredto convert power between an external power supply, a storage battery,and a motor, in addition to a storage battery for supplying power. Sucha power conversion apparatus is provided with a charging circuit thatgenerates a charging voltage for the storage battery from the externalpower supply or an inverter circuit that converts a direct current ofthe storage battery to a three-phase alternating-current and outputs thecurrent to the motor, for example.

The power conversion apparatus includes a power conversion circuit towhich a high voltage is applied or in which a high voltage is generated,so that it is a common practice to configure the power conversioncircuit to be covered by a casing (see, e.g., Japanese PatentApplications Laid-open No. 2003-009301 and No. 2005-143200). The casingis ensured for airtightness in order to prevent entry of a water drop ordust, for example.

During a vehicle assembly process, a process of assembling a powerconversion apparatus of a production unit to a vehicle may include astep of connecting a power output cable (e.g., output cable forsupplying a driving current to a motor) to the power conversionapparatus. A cable through which a large current flows requires sureconnection. For this reason, as a connection method for such a cable, aconnection method of inserting a cable into a casing of a powerconversion apparatus and directly connecting the cable to a connectionportion is employed, normally, instead of a connection method using aconnector. Connecting a cable to the connection portion is performed byinserting a screw driver or the like through a work window of thecasing.

The connection portion is provided at a plurality of positions, e.g.,three connection portions where three-phase alternating-current isoutputted. The plurality of connection portions are disposed while beingspaced apart from each other in general in consideration of securing apredetermined insulation distance or of the influence of a magneticfield. For this reason, the work window for a plurality of connectionportions is formed as a window hole that is long in a direction wherethe connection portions are aligned or a plurality of window holesaligned in a direction identical to that of the plurality of connectionportions.

When the casing of the power conversion apparatus is provided with awork window, an interlock mechanism is required, which ensures safetywhen the work window is opened. To be more specific, such an interlockmechanism is a mechanism in which an interlock switch turns and blockssupply of power when the lid of the work window is removed.

However, when the work window is formed in a range that is long in acertain direction, there arises a problem of how a lid partially formingthe interlock mechanism should be formed.

For example, when a configuration is employed in which a metal lid isadopted and fastened to the casing via a gasket, high airtightness canbe ensured. However, providing the lid with a mechanism (e.g.,protrusion) to turn an interlock switch makes molding difficult comparedwith the case where the lid is made of resin, and causes an increase inthe number of manufacturing steps, thus causing an increase in costs.

Meanwhile, when a configuration is employed in which a resin-made lidincluding an O-ring is fastened to the casing, the mechanism (e.g.,protrusion) to turn an interlock switch can be formed in the lid withlow costs and a high degree of freedom by resin molding. For example, aprotrusion having an optimum shape can be easily formed in the lid.However, when a lid that is long in a certain direction such as arectangular shape is to be sealed, an O-ring having a similar shapeneeds to be prepared. In this case, there arises a problem in that it isdifficult to keep the airtightness by the O-ring as the length of thecertain direction becomes long.

Moreover, when a plurality of sets of work windows and lids are to beindependently provided for a plurality of connection portions, therearises a problem in that it is required to prepare the number ofinterlock mechanisms for the number of lids.

For the reasons mentioned above, in Embodiment 2, it is made possible toensure airtightness for a work window of a power conversion apparatusand to achieve easiness of the manufacturing of an interlock mechanism.

Description of Embodiment 2

The basic configuration of power conversion apparatus 100 according toEmbodiment 2 is similar to the configuration illustrated in FIG. 1, sothat the description will not be repeated. Hereinafter, a descriptionwill be given of differences from Embodiment 1.

[Configuration of Work Window]

In power conversion apparatus 100 according to Embodiment 2, casing 11includes two work windows 111 and 112 for directly connectingthree-phase output cables 42 to inverter 13 as illustrated in FIG. 6.

FIG. 7 is an exploded perspective view illustrating a structure of thework windows and lids of the power conversion apparatus according toEmbodiment 2. FIG. 8 is a perspective view illustrating how the lids arefixed to the work windows. FIG. 9 is a front view illustrating the workwindows. FIG. 10 is a front view illustrating how a first lid is fixedto a work window. FIG. 11 is a front view illustrating first and secondlids are fixed to the work windows.

As illustrated in FIG. 9, work windows 111 and 112 are through holespassing through casing 11 from outside of casing 11 to inside thereof.Work windows 111 and 112 are formed at positions where three connectionportions 131 face work windows 111 and 112. Three connection portions131 are regions where connection terminals 42 a of three output cables42 for transmitting a three-phase alternating-current to motor 40 andthe output terminals of inverter 13 are fixedly attached together usingscrews, for example.

Three connection portions 131 are disposed while being spaced apart fromeach other because of the magnetic influence and a need to secure apredetermined insulation distance. Three connection portions 131 arealigned in a row in parallel with a substrate of inverter 13.

Three output cables 42 are inserted into the inside of casing 11 viathree through holes at a lower portion of casing 11, respectively. Theairtightness for the three through holes is secured by fastening threecable clamps 42 b.

Work window 111, which is one of the two work windows (hereinafter, maybe referred to as “first work window 111”) has an elongated hole shapethat is long in a certain direction. More specifically, work window 111has a rectangular shape that is long in the direction in which threeconnection portions 131 are aligned (rectangular with rounded corners).Two connection portions 131 face work window 111.

The other one of the work windows, which is work window 112(hereinafter, may be referred to as “second work window 112”) is a holehaving substantially the same vertical and horizontal lengths. Morespecifically, work window 112 has substantially a circular shape, or anellipse shape which has a slightly long side in a certain direction thanin the other direction. One connection portion 131 faces work window112.

[Configuration of Lid of Work Window]

As illustrated in FIG. 7, casing 11 includes a plurality of lids 51 and52 for closing work windows 111 and 112, respectively.

First lid 51 is provided for closing first work window 111 and is ametal lid formed by processing a plate. Lid 51 is fastened to casing 11via bolts or the like with highly rigid gasket 511 interposedtherebetween. Note that, as long as the material has rigidity, lid 51does not have to be metal.

Second lid 52 is provided for closing second work window 112 and isintegrally molded using a resin. Note that, lid 52 includes projection522 (equivalent to an operation portion), which pushes interlock switch135 (see FIG. 12), to be described, hereinafter. Lid 52 may be formed tohave both a metal portion and a resin portion by insert molding oroutsert molding.

Lid 52 is fastened to casing 11 via bolts. Elastic O-ring 521 (e.g.,rubber O-ring) is fitted to lid 52. O-ring 521 is placed between lid 52and work window 112, thus sealing the gap between lid 52 and work window112.

Lid 52 includes superimposed portion 52 a, which is superimposed overone of the lids, lid 51 (hereinafter, may be referred to as “first lid51”) when lid 52, which is the other one of the lids (hereinafter, maybe referred to as “second lid 52”) is fastened to casing 11.Superimposed portion 52 a is configured to be superimposed overfastening portion 51 a of lid 51 (outside of the casing), e.g.,superimposed over the bolts used for fastening lid 51. With thisconfiguration, as illustrated in FIGS. 8 and 11, while lid 52 isfastened, bolts for first lid 51 are hidden to prevent lid 51 from beingunfastened. More specifically, this structure prevents first lid 51 frombeing opened unless lid 52 is opened.

Projection 113 is formed near work window 112 corresponding to lid 52 soas to prevent lid 52 from being attached to the wrong side.

[Configuration of Interlock Mechanism]

FIG. 12 is a plan view illustrating an interlock mechanism of the powerconversion apparatus according to Embodiment 2.

Power conversion apparatus 100 according to Embodiment 2 includes aninterlock mechanism for ensuring safety when work windows 111 and 112are released.

The interlock mechanism includes: interlock switch 135, which isdisposed inside casing 11; and projection 522, which responds tointerlock switch 135 and turns the switch.

Interlock switch 135 is a contact switch that turns when arm 135 a ispushed in, for example. Inverter 13 includes a blocking circuit thatallows input of power to the inverter when arm 135 a is pushed in andthat blocks input of power to the inverter when arm 135 a, which hasbeen pushed in is released.

As has been described above, projection 522 is formed in lid 52 andprotrudes into the inside of casing 11 from work window 112 so as topush arm 135 a of interlock switch 135 while lid 52 is fastened.

Interlock switch 135 may not be a contact switch and may be a proximitysensor switch that turns the state of the switch when projection 522comes closer to the switch.

[Installation Process to Vehicle]

As in Embodiment 1, power conversion apparatus 100 according toEmbodiment 2 is installed in a vehicle. The installation of powerconversion apparatus 100 will be described with reference to FIGS. 5Aand 5B, hereinafter.

Vehicle 1 illustrated in FIG. 5A is an example in which running motor 40is disposed near a front wheel axle. Battery 30 is installed in a bottomportion (e.g., under the passenger seat) of vehicle 1. In this case, itis favorable to install power conversion apparatus 100 at a frontposition of vehicle 1 that allows power conversion apparatus 100 to beconnected to motor 40 with the shortest distance.

Vehicle 1 in FIG. 5B is an example in which running motor 40 is disposednear a rear wheel axle. Battery 30 is installed in a bottom portion(e.g., under the passenger seat) of vehicle 1. In this case, it isfavorable to install power conversion apparatus 100 at a rear positionof vehicle 1 that allows power conversion apparatus 100 to be connectedto motor 40 with the shortest distance.

In the step of installing power conversion apparatus 100 in vehicle 100,the step of connecting output cable 42 to inverter 13 is required afterinstallation of power conversion apparatus 100 of a unit production tovehicle 1 or during the installation.

In the step of connecting the cable, as illustrated in FIGS. 7 and 9,while lids 51 and 52 are released, the operator connects connectionterminals 42 a of three output cables 42 to connection portions 131 ofinverter 13. Since lid 52 is removed, interlock switch 135 is turnedoff, thus blocking input of power to inverter 13. Accordingly, theconnection work can be performed while safety is ensured.

Upon completion of the connection work, as illustrated in FIG. 10, theoperator fastens first lid 51 to casing 11. Next, as illustrated in FIG.11, second lid 52 is fastened to casing 11. Fastening the lids to casing11 can ensure high airtightness for casing 11. Fastening second lid 52to casing 11 turns on interlock switch 135 and enables power supply toinverter 13.

As described above, with power conversion apparatus 100 according toEmbodiment 2, second lid 52 is fastened so as to partially overlap firstlid 51. Accordingly, providing the interlock mechanism that interlockswith the opening and closing of second lid 52 alone makes it possible toensure safety related to opening of work windows 111 and 112. Morespecifically, first lid 51 cannot be removed unless second lid 52 isremoved.

Moreover, in Embodiment 2, a plurality of lids 51 and 52 are providedfor closing work windows 111 and 112, respectively. Thus, even in aconfiguration in which work windows 111 and 112 are each formed in arange that is long in a certain direction for a plurality of connectionportions disposed while being spaced apart from each other, second lid52, which requires the operation portion (e.g., protrusion) of theinterlock mechanism, can be formed in a small shape (or a shape havingsubstantially the same vertical and lateral dimensions). Thus, use of aresin-made lid for second lid 52 allows the operation portion (e.g.,projection) of the interlock mechanism to be formed easily at low costsand also makes it possible to ensure high airtightness easily with anO-ring.

In Embodiment 2, first lid 51, which requires no operation portion(e.g., projection) of the interlock mechanism, and work window 111,which corresponds to first lid 51, are formed in a shape that is long ina certain direction and placed at a position where two connectionportions 131 face lid 51 and work window 111. Thus, the number ofcomponents can be reduced, and the efficiency of connection work isimproved as well.

Embodiment 2 of the present invention has been described thus far, butthe description provided above is only an example. Accordingly, thefollowing modifications are possible, for example.

In Embodiment 2, the configuration in which power supply to inverter 13is blocked when work windows 111 and 112 are opened has been describedas an example of the interlock mechanism. However, the interlockmechanism may be configured to block at least application of a highvoltage to connection portions 131.

In Embodiment 2, the configuration including two work windows 111 and112, and two lids 51 and 52 has been described as an example, but aconfiguration including “n” work windows and “n” lids (where “n” is anatural number equal to or greater than three) may be employed. In thiscase, the “n” lids are each configured to partially overlap another lidand are configured in such a manner that the lids except the last lidcannot be removed unless another lid is removed. In this configuration,the operation portion (e.g., projection) of the interlock mechanism isformed in the lid to be fastened last.

Moreover, in Embodiment 2, a configuration including two work windows111 and 112 and two lids 51 and 52 has been described as an example, buta configuration including one work window and two lids may be employed.In this configuration, while a first lid covers the entire circumferenceof one work window, a through hole serving as a small work window may beformed in a part of the first lid, and a second lid is configured tocover the work window formed in the first lid.

In Embodiment 2, the configuration in which second lid 52 partiallyoverlaps fastening portion 51 a (bolts) of first lid 51 has beendescribed as an example. However, it is also possible to employ aconfiguration in which second lid 52 overlaps a portion of first lid 51other than the fastening portion of first lid 51, thereby making firstlid 51 unremovable unless second lid 52 is removed. Moreover, it is alsopossible to employ a configuration in which first and second lids 51 and52 are configured to be collectively fastened to casing 11 at a portionwhere first and second lids 51 and 52 overlap each other. For example, aconfiguration in which insertion holes that overlap each other areformed in first and second lids 51 and 52, respectively, and one bolt isinserted through both of the insertion holes to fasten first and secondlids 51 and 52 to casing 11.

In Embodiment 2, work windows 111 and 112 have been described as workwindows for connection of output cables 42 of motor 40, a work windowfor connection of a terminal of a harness for power input, or workwindows for various purposes may be provided.

Moreover, in Embodiment 2, inverter 13, charging apparatus 14, andjunction box 15 have been described as examples of the circuit to behoused in a casing of the power conversion apparatus. However, as acircuit to be housed in a casing of the power conversion apparatus, onlyan inverter or a charging apparatus, or various high voltage circuits towhich a high voltage is applied or in which a high voltage is generatedmay be employed.

Summary of Aspects of the Invention

Next, a description will be given of an overview of aspects according tothe present invention.

A power conversion apparatus according to a first aspect includes: acharging apparatus that charges a battery using an external powersupply; an inverter that converts a current of the battery from a directcurrent to an alternating-current and that supplies thealternating-current to a motor; and a junction box that relayselectrical connection, in which the inverter, the charging apparatus,and the junction box are housed in a single casing, and the chargingapparatus and the junction box are electrically connected to each otherwhile the junction box and the inverter are electrically connected toeach other, in which the junction box and the inverter are connected toeach other via a bus bar.

A power conversion apparatus according to a second aspect is the powerconversion apparatus according to the first aspect further including aDC/DC converter in the casing.

A power conversion apparatus according to a third aspect is the powerconversion apparatus according to the first aspect in which the chargingapparatus and the inverter are each connected to the battery via thejunction box.

A power conversion apparatus according to a fourth aspect is the powerconversion apparatus according to the first aspect in which the batteryis installed in a rear portion or a bottom portion of a vehicle, and thejunction box is installed at a position that allows the junction box tobe connected to the battery in the casing with a shortest distancebetween the junction box and the battery.

A power conversion apparatus according to a fifth aspect is the powerconversion apparatus according to the first aspect, in which the casingis internally divided into a plurality of spaces by a partition member,in which the casing includes the inverter and the junction box indifferent spaces, respectively, and the inverter and the junction boxare connected to each other via the bus bar that passes through anopening formed in the partition member.

A power conversion apparatus according to a sixth aspect is the powerconversion apparatus according to the fifth aspect, in which a portionof the partition member where the opening is formed is insulated andcoated.

A power conversion apparatus according to a seventh aspect is the powerconversion apparatus according to the fifth aspect, in which thejunction box at least includes a portion that includes an insulationportion, that is inserted through the opening, and that serves as aconnection portion for the bus bar.

A power conversion apparatus according to an eighth aspect is the powerconversion apparatus according to the fifth aspect, in which the casingis internally divided into a first space and a second space by thepartition member, a first casing that forms the first space and a secondcasing that forms the second space are separable from each other, andthe first and the second casings include fastening portions in the firstand the second spaces, respectively, the fastening portions beingincluded for fastening the first and the second casings together.

A power conversion apparatus according to a ninth aspect is the powerconversion apparatus according to the eighth aspect, in which the secondcasing includes a lid, in which, when the second casing is fastened tothe first casing while being superimposed on the first casing, only thesecond casing includes an interlock that detects an open state of thelid of the second casing.

A power conversion apparatus according to a tenth aspect is the powerconversion apparatus according to the first aspect further including: awork window that is formed in the casing and that passes through thecasing from an outer side of the casing to an inner side of the casing;a plurality of lids for closing the work window; and an interlockmechanism that interlocks with open and closed states of the pluralityof lids, in which the plurality of lids include a first lid and a secondlid that is fixed to the casing while superimposed over a part of thefirst lid, in which the interlock mechanism includes: an interlockswitch disposed inside the casing; and an operation portion that isformed in the second lid, the operation portion being configured torespond to the interlock switch and to turn the interlock switch.

A power conversion apparatus according to an eleventh aspect is thepower conversion apparatus according to the tenth aspect furtherincluding a fastening portion at a portion where the second lid overlapsthe first lid, the fastening portion being configured to fasten thefirst lid to the casing.

A power conversion apparatus according to a twelfth aspect is the powerconversion apparatus according to the tenth aspect further includingthree connection portions facing the work window, the three connectionportions being used for a three-phase cable for conducting a three-phasealternating-current, in which the work window includes a window holethat is long in one direction or a plurality of window holes that arealigned in one direction or combination of the window hole and theplurality of widow holes.

A power conversion apparatus according to a thirteenth aspect is thepower conversion apparatus according to the twelfth aspect, in which thefirst lid is a metal lid and closes a portion of the work window wheretwo of the three connection portions face the work window, and thesecond lid includes at least a resin-made portion and closes a portionof the work window where the remaining connection portion of the threeconnection portions faces the work window.

A power conversion apparatus according to a fourteenth aspect is thepower conversion apparatus according to the tenth aspect, in which thefirst lid is a metal lid that is fixed to the casing with a gasketinterposed between the lid and the casing, and the second lid includesat least a resin-made portion and is fixed to the casing with an O-ringinterposed between the lid and the casing.

A power conversion apparatus according to a fifteenth aspect is thepower conversion apparatus according to the first aspect, in which theinverter is an inverter circuit that outputs the alternating-current tothe motor to be installed in a vehicle.

A junction box according to a sixteenth aspect includes a protrudingportion to be inserted into an opening formed in a partition member of acasing that is internally divided into a plurality of spaces by thepartition member, in which the protruding portion includes an insulationportion and serves as a connection portion for a bus bar.

The disclosures of Japanese Patent Applications No. 2013-078544, filedon Apr. 4, 2013, No. 2013-078546, filed on Apr. 4, 2013, and No.2013-140526, filed on Jul. 4, 2013 including the specifications,drawings and abstracts, are incorporated herein by reference in theirentireties.

INDUSTRIAL APPLICABILITY

The present invention is applicable to a power conversion apparatus tobe installed in a vehicle.

REFERENCE SIGNS LIST

-   1 Vehicle-   10 Partition member (bottom member)-   11, 12 Casing-   13 Inverter-   14 Charging apparatus-   15 Junction box-   16 Bus bar-   17 Opening-   18 Lid-   19 External power supply connection portion-   20 External power supply-   21 Screw-   22 Screw hole-   23 Insulation portion-   24 Protruding portion-   30 Battery-   40 Motor-   42 Output cable-   42 a Connection terminal-   42 b Cable clamp-   51 Lid (first lid)-   51 a Fastening portion-   52 Lid (Second lid)-   522 Projection (operation portion)-   52 a Superimposed portion-   100 Power conversion apparatus-   111, 112 Work window-   113 Projection-   131 Connection portion-   135 Interlock switch-   135 a Arm-   511 Gasket-   521 O-ring

1. A power conversion apparatus comprising: a charging apparatus thatcharges a battery using an external power supply; an inverter thatconverts a current of the battery from a direct current to analternating-current and that supplies the alternating-current to amotor; and a junction box that relays electrical connection, wherein theinverter, the charging apparatus, and the junction box are housed in asingle casing, and the charging apparatus and the junction box areelectrically connected to each other while the junction box and theinverter are electrically connected to each other, wherein the junctionbox and the inverter are connected to each other via a bus bar.
 2. Thepower conversion apparatus according to claim 1, further comprising aDC/DC converter in the casing.
 3. The power conversion apparatusaccording to claim 1, wherein the charging apparatus and the inverterare each connected to the battery via the junction box.
 4. The powerconversion apparatus according to claim 1, wherein the battery isinstalled in a rear portion or a bottom portion of a vehicle, and thejunction box is installed at a position that allows the junction box tobe connected to the battery in the casing with a shortest distancebetween the junction box and the battery.
 5. The power conversionapparatus according to claim 1, wherein the casing is internally dividedinto a plurality of spaces by a partition member, wherein the casingincludes the inverter and the junction box in different spaces,respectively, and the inverter and the junction box are connected toeach other via the bus bar that passes through an opening formed in thepartition member.
 6. The power conversion apparatus according to claim5, wherein a portion of the partition member where the opening is formedis insulated and coated.
 7. The power conversion apparatus according toclaim 5, wherein the junction box at least includes a portion thatincludes an insulation portion, that is inserted through the opening,and that serves as a connection portion for the bus bar.
 8. The powerconversion apparatus according to claim 5, wherein the casing isinternally divided into a first space and a second space by thepartition member, a first casing that forms the first space and a secondcasing that forms the second space are separable from each other, andthe first and the second casings include fastening portions in the firstand the second spaces, respectively, the fastening portions beingincluded for fastening the first and the second casings together.
 9. Thepower conversion apparatus according to claim 8, wherein the secondcasing includes a lid, wherein, when the second casing is fastened tothe first casing while being superimposed on the first casing, only thesecond casing includes an interlock that detects an open state of thelid of the second casing.
 10. The power conversion apparatus accordingto claim 1, further comprising: a work window that is formed in thecasing and that passes through the casing from an outer side of thecasing to an inner side of the casing; a plurality of lids for closingthe work window; and an interlock mechanism that interlocks with openand closed states of the plurality of lids, wherein the plurality oflids include a first lid and a second lid that is fixed to the casingwhile superimposed over a part of the first lid, wherein the interlockmechanism includes: an interlock switch disposed inside the casing; andan operation portion that is formed in the second lid, the operationportion being configured to respond to the interlock switch and to turnthe interlock switch.
 11. The power conversion apparatus according toclaim 10, further comprising a fastening portion at a portion where thesecond lid overlaps the first lid, the fastening portion beingconfigured to fasten the first lid to the casing.
 12. The powerconversion apparatus according to claim 10, further comprising threeconnection portions facing the work window, the three connectionportions being used for a three-phase cable for conducting a three-phasealternating-current, wherein the work window includes a window hole thatis long in one direction or a plurality of window holes that are alignedin one direction or combination of the window hole and the plurality ofwidow holes.
 13. The power conversion apparatus according to claim 12,wherein the first lid is a metal lid and closes a portion of the workwindow where two of the three connection portions face the work window,and the second lid includes at least a resin-made portion and closes aportion of the work window where the remaining connection portion of thethree connection portions faces the work window.
 14. The powerconversion apparatus according to claim 10, wherein the first lid is ametal lid that is fixed to the casing with a gasket interposed betweenthe lid and the casing, and the second lid includes at least aresin-made portion and is fixed to the casing with an O-ring interposedbetween the lid and the casing.
 15. A junction box comprising aprotruding portion to be inserted into an opening formed in a partitionmember of a casing that is internally divided into a plurality of spacesby the partition member, wherein the protruding portion includes aninsulation portion and serves as a connection portion for a bus bar.